The goal of this project is to determine the molecular site of ethanol action on AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) glutamate receptor. AMPA receptor is a ligand-gated ion channel that mediates the majority of fast excitatory glutamatergic neurotransmission in the mammalian central nervous system (CNS) and plays a central role in synaptic plasticity and stabilization, learning and memory. Ethanol is the most widely abused drug in the world, but the CNS mechanisms responsible for the behavioral effects of alcohol such as intoxication, amnesia and physical dependence is unknown. It is however known that ethanol has a depressant effect on mammalian brain, receptors, including ionotropic glutamate receptors of which AMPA receptor belong. Although AMPA receptor currents are inhibited by ethanol, the mechanism of ethanol inhibition and the site of ethanol interaction on the receptor are unknown. The major goal of this proposal is to investigate the site of ethanol interactions on AMPA receptor subunits and use Ns knowledge to postulate a mechanism for ethanol effect on AMPA receptors in the brain. We propose to study target sites for ethanol on AMPA receptors by these Specific Aims. Specific Aim 1. To use truncated carboxyl (C) terminal domain receptor subunit mutants to study receptor sensitivity to ethanol and determine whether the intracellular C-terminal domain is the target site for ethanol inhibition of AMPA receptor. Specific Aim 2. To use truncated alternative splice variable region of AMPA receptor subunits to study receptor sensitivity to ethanol and determine whether the amino acids constituting the extracellular "flip/flop" region is the target site for ethanol inhibition of receptor function. The results of these studies will answer some questions on the contribution of the intracellular and extracellular domains of the AMPA receptor to the inhibitory effects of ethanol. This grant will contribute significantly to the career establishment and development of the investigator by providing the time, salary support and supplies needed for education and training in alcohol research in a minority institution.